1. Field of the Invention
The present invention relates in general to handpieces for cataract surgery and, in particular, to ultrasonic handpieces which can be easily cleaned and provide improved and more efficient routing of fluids through irrigation and aspiration channels to and from a patient's eye.
2. Description of Related Art and Other Considerations
A typical ultrasonic handpiece used in ophthalmic surgery includes a housing, an ultrasonic driver assembly centered within the housing, a rear part or cap at one end of the housing, a front part with a cataract needle at the other end of the housing, and an irrigation conduit extending between the front and the rear parts.
The rear part furnishes irrigating fluid to the front part for supply to the eye, receives the fluid after being flushed through the eye, and seals about an electrical connection between the driver assembly and an exterior source of power. The front part with a cataract needle is adapted to penetrate the patient's eye for supplying ultrasonic vibrations thereto and for channelling the fluid into and out of the eye.
An external tube may be attached to the exterior of the housing, or an annular space may be provided between concentrically arranged tubular shells disposed about the ultrasonic driver assembly. Irrigation tubes exterior to the housing are known to interfere with the surgeon's fingers during operation. While ultrasonic handpieces with concentrically arranged tubular shells avoid this problem, they and the exterior tubes are subject to other problems.
It is important that the irrigating fluid flow as evenly and uniformly as possible, and at a sufficiently rapid rate so as to ensure removal of the fragmented lens from the patient's eye, and at a sufficiently high pressure to prevent collapse of the eye during the surgery, as is known and required by practitioners using and manufacturers of such ophthalmic instruments. It is further important that the handpiece be easily cleaned, without wetting or otherwise harming its driver assembly, in particular.